Along with the development of flat panel display industry, the performance requirement of the display panel is continuously increasing. So that, there is a high requirement of the carrier mobility of the thin film transistor within the display panel.
At present, conventional thin-film-transistor (TFT) is amorphous silicon TFT, which means the active layer of the TFT is made by amorphous silicon material. Generally, the carrier mobility of the amorphous silicon thin film transistor is low. Typically, the electron mobility is between 0.1 cm2V−1s−1 and 1 cm2V−1s−1, which is not able to meet the current requirement of flat panel display industry. Therefore, low-temperature polysilicon (LTPS) TFT and oxide TFT are developed.
The material of the active layer of LTPS TFT is low-temperature polysilicon, which is transformed from amorphous silicon at a low temperature. LTPS TFT can have a high carrier mobility which is about 100 cm2V−1s−1 to 500 cm2V−1s−1. However, a serious problem of LTPS TFT is that the uniformity is not good, which blocks the application of LTPS TFT in the large-size display panel area.
On the other hand, the material of the active layer of oxide TFT is oxide semiconductor. Ensuring a good uniformity within a large size, an oxide TFT can also have a carrier mobility of 10 cm2V−1s−1. Due to high carrier mobility, good uniformity, transparency, and simple fabricating process, the oxide TFT can meet the needs of the large-size display panel area.
In the existing production process for fabricating TFT, a sputtering method is used for forming the metal oxide semiconductor layer. Therefore, the semiconductor channel layer, the gate electrode, the source electrode and the drain electrode are all be formed in a same device, such as a sputtering device. However, because of the material of the insulating layer of oxide TFT is silicon dioxide (SiO2) or silicon nitride (SiNx), the insulating layer has to be formed by using plasma enhanced chemical vapor deposition (PECVD), which means a high production cost. Further, PECVD method requires a high temperature to form SiO2 or SiNx. Consequently, the oxide TFT cannot be formed on a flexible substrate.
Accordingly, it is desirable to provide a thin-film-transistor (TFT), a related TFT array substrates, a fabricating method thereof, and a related display panels.